The present invention relates to a steering device for a row crop cultivator and more particularly to a steerable coulter disc on the tool bar of a hitch mounted implement and means responsive to drifting movement of the tool bar transversely of the crop rows for steering the coulter disc to limit such drift and to move the tool bar back to its intended working position.
There is seen in modern farming practice a growing trend toward the use of larger and wider farm implements adapted to be pulled by the largest and most powerful of the tractors presently being produced. Many of the four wheel drive articulating type tractors, in particular, are capable of pulling planter implements adapted for planting up to twelve or sixteen rows at a time. Corresponding twelve and sixteen-row cultivator implements are available for such tractors.
With the advent of the longer tool bars associated with the wider implements, there is a need for more sophisticated means of steering the implements. The tool bar, which is mounted on the three point hitch of the tractor, may carry ground working tools spaced as close as four inches apart over the even row on twelve-row and larger machines. The tractor operator is generally situated in a cab located several feet above and forwardly of the tool bar such that the working engagement of the tools with the ground is not visible to him. All the operator can do is to attempt to keep the tractor centered relative to the rows. The problem of maintaining the ground working tools between the rows is even more critical with the articulating type tractors wherein the rear axle may tend to pivot relative to the front axle during normal steering of the tractor. Such pivotal movement may laterally shift the tool bar to the extent that the tools are moved into the crop rows. Accordingly, substantial crop loss is risked with each cultivating operation.
It is an object of the present invention to minimize and compensate for lateral shifting of the tool bar by providing a steering apparatus for a row crop cultivator which is capable of stabilizing the rear axle of the towing tractor by absorbing transverse pressure exerted by the tractor rear axle and centering the tractor to correct any lateral drift caused by such pressures.
Another object of the invention is to provide a steering apparatus for a hitch mounted implement which is automatically responsive to transverse drifting movement of the tool bar to correctively steer the implement back to a working position wherein the ground working tools are centered between the crop rows.
A further object of the invention is to provide a steering apparatus which includes a mechanism for following a guide furrow formed by a row marker on the planter implement and signaling any lateral displacement of the tool bar relative to the guide furrow.
A further object of the invention is to provide a steering apparatus which is vertically adjustable with respect to the tool bar so that the coulter discs associated with the steering apparatus may be maintained at a uniform depth in the ground for various working depths of the tools.
A further object of the invention is to provide a steering apparatus which is adjustable to increase or decrease the corrective steering of the coulter discs in response to a fixed transverse displacement of the tool bar.
A further object of the invention is to provide a steering apparatus which is economical to manufacture, durable in use and efficient in operation.
These and other objects of the present invention will be apparent to those skilled in the art.